Brain lesions modifying the abstinence signs in morphine-dependent rats

L. F. Tseng, M. K. Menon, H. H. Loh

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Abstinence signs, mastication (teeth chattering), myoclonic twitch and repetitive shaking movements (wet shakes) were precipitated by naloxone and were recorded electromyographically from the suprahyoideal muscle in morphine-dependent rats anaesthetized with urethane. Transverse brain lesions were made bilaterally with an iridectomy knife in urethane anaesthetized morphine-dependent rats. Lesions at the level of the anterior commissure did not inhibit the myoclonic twitch and mastication but markedly potentiated wet shakes. Lesions which separated the connection between the corpus striatum and the thalamus completely abolished mastication, but the twitching activity and wet shakes were not affected. Mid-thalamus lesions did not inhibit wet shakes and mastication, but the myoclonic twitch activity was markedly reduced. Lesions at the mid-collicular level abolished all of the three activities observed. The results suggest that different precipitated withdrawal signs may originate from different brain areas.

Original languageEnglish (US)
Pages (from-to)247-250
Number of pages4
Issue number4
StatePublished - Apr 1975


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